ASMR
by KudaKano
Summary: Honey experiments on Hiro and Tadashi.


**I got the idea for this quick fic while I was working on the next part of 'Yellow Eyed Spy' so I had to stop and write it up 0_0 **

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><p>"So…what's all this for?"<p>

Hiro asked as Honey continued placing sticky patches with metal chips on various part of his skin.

Honey had brought Hiro and Tadashi to a secluded room in the San Fransokyo Tech workshop. It was narrow with thick walls to keep out the sound of other students working on their projects.

"Oh! These are wireless transmitters." She said as she placed three clips in the back of his hair.

"They'll help me track your body's sensory responses. _Cool_ right?"

Hiro wasn't sure if he liked how excited she was.

"How did I end up as Honey's lab rat, again?" He looked up at Tadashi just as Honey lifted up the back of his shirt and started sticking more transmitters along his spine.

"I gave you a fantastic recommendation." Tadashi replied with a smile. He was covered with the same patches that Honey was placing on Hiro. They were stuck to the back of his neck along with three metal clips in his hair. Hiro could see small bumps beneath his brother's shirt where more transmitters were placed along his shoulders and back.

"I can always count on you." Hiro said sarcastically.

He looked at the center of the room where a single chair sat surrounded by odd-looking equipment and monitors.

"This study doesn't include…torture…right?"

Tadashi laughed and Honey walked over to one of the monitors and began entering a code.

"Oh no, quite the opposite actually!" She replied. "Have you ever heard of the term ASMR?"

Hiro shook his head.

"Well it's mostly how your body reacts to certain sounds and triggers. It's supposed to be relaxing, not painful."

Honey gestured to the chair and Hiro sheepishly took a seat.

Hiro shifted uncomfortably and looked back and forth between Honey and Tadashi. The room was bright with white walls and he felt very much like a patient in a hospital.

"This monitor will show me how strongly your body responds to certain triggers." Honey gestured to the blue screen positioned next to the chair. It had a single line across the monitor with various data listed in the corners.

He nodded, still unsure if he was going to like what Honey would do to him.

"Okay, I just need you to relax, Hiro." Honey said as she took out a notebook and began scribbling down information.

"Relax. Got it." Hiro murmured. However, he was swinging his feet back and fourth and tapping his fingers along the chair.

Tadashi smiled as he watched Hiro squirm about. His brother was always high strung and eager to get from one place to the next. He rarely took the time to relax and that was the main reason Tadashi has recommended him for Honey's study.

"You _do_ remember what relaxed is, right?" Tadashi asked as he walked behind the chair.

Hiro stuck his tongue out but then his brother's hands engulfed his shoulders and he stopped moving.

Tadashi began rubbing Hiro's shoulders in an effort to relax him. He often did this before bed when his brother was too hyper to fall asleep. By now, he knew all of the tender spots between Hiro's shoulders that would turn the boy into Jell-O.

Hiro deflated as Tadashi worked the kinks out of his back. He had to admit, his brother could give a _mean_ shoulder massage. Tadashi dug his thumb into a spot just about Hiro's right shoulder blade that made the boy bite his lip to keep from moaning. He didn't want to make such an embarrassing sound with Honey in the room.

Tadashi waited until Hiro's body was completely motionless and his eyes had fallen shut before releasing him.

Honey watched the whole thing in amazement. She was used to Hiro always running and bouncing around on his feet but now the boy's hands were motionless in his lap and his legs dangled limply from the chair. She had never seen him in such a relaxed state.

Tadashi could work wonders…or maybe it was just a brother thing.

"Okay Hiro, you can keep your eyes closed while we start. Just stay relaxed and focus on the sounds." Honey instructed.

"Mm-hmm." Hiro replied low in his throat. If this study included more back rubs then he wasn't about to complain.

"I think it'll work best if we speak quietly." Honey whispered to Tadashi and he nodded.

"Lets see…" Honey flipped to a page in her notebook and looked through a list of trigger words.

She held her finger on one and then bent down so she could be level with Hiro's left ear.

"Popsicle." Honey whispered softly right in front of Hiro's ear.

Hiro immediately drew away and giggled. He wasn't expecting her to be so close nor to say such a silly word.

Honey frowned and then used her pen to scratch a line through the word on her notebook.

She selected another word and tried again. This time the words was "Ornament" but Hiro's reaction was the same.

Hiro actually thought the sound of Honey's voice was nice but he wasn't used to having girls whisper into his ear and it started to bring him out of his relaxed state.

"Let me try." Tadashi whispered and Honey handed him her notebook.

He looked through the list of words before leaning down next to Hiro's other ear.

"_Secret_." Tadashi whispered.

Hiro wasn't sure if it was the way his brother dragged out the 's' sound in the word or if it was because Tadashi's voice was lower pitched and familiar, but the sound immediately caused a wave of pleasant prickles to flow down the back of Hiro's neck.

Honey smiled when she saw a spike appear on the monitor. She took notes with her pen and decided that the type of word was less important then the delivery.

Hiro could hear her walk towards Tadashi and whisper instructions to him.

Then he could feel his brother's breath next to his ear again.

"Spectacle." Tadashi's deep voice whispered.

This time, instead of dragging it out, Tadashi said it quickly and let the word click off his tongue.

This word had a greater effect and caused more tingles to dance though the back of Hiro's head. Hiro focused on the feeling and waited for it to happen again.

Tadashi moved his head and began whispering the same word at different distances from Hiro's ears. Eventually he simply started whispering "sks" all around his little brother's head. Tadashi smiled as he watched the line on the monitor spike wildly every time he made a sound.

It felt like Hiro's body was actually warmed up because now he was starting to feel a reaction from _everything_. The sound of Honey's pen taking notes, the quiet footsteps as the two students walked around him, and even the sound from the fabric of his brother's shirt was causing pleasant tingles around his back, shoulders, and scalp.

Hiro welcomed it all. He had never felt so relaxed. If he were lying down he would probably be asleep by now.

Tadashi was probably having too much fun watching Hiro's reactions on the monitor. However, he was also taking mental notes for the next time he had to coax his brother into sleeping.

He brushed a strand of black hair away from his brother's ear. He was about to whisper again but he paused when he saw the line on the monitor spike higher than all of the others.

"Whoa! Do that again." Honey whispered.

Suddenly Tadashi's hands were carding through his brother's dark hair and Hiro's body erupted with tingles.

Oh, hair touching was _wonderful_.

Hiro let out a sigh as Tadashi continued tugging gently at the strands along the back of his scalp. The pleasant prickles raced down Hiro's neck, shoulders, spine, and even up the sides of his legs.

Tadashi and Honey both watched in amazement as the monitor line shot all the way to the top of the screen.

"Heh, I've found your weakness, Hiro." Tadashi whispered.

Hiro remained silent, still completely focused on the feeling. He let his chin rest against his collar to give his brother more access to his messy black hair.

"Okay, you two can probably switch now." Honey stated.

She pressed a few buttons on the monitor and it reset with a loud _beep_.

Hiro tried not to feel too disappointed when Tadashi stopped touching his hair. He wasn't sure if he would be able to move…his body felt numb and some of the tingling remained.

Tadashi stretched and then smirked when he noticed Hiro was still sitting with his eyes closed.

He grinned evilly before sticking a finger in his mouth and promptly shoving it into his brother's left ear.

Hiro gave a very un-manly shriek and was off the chair a second later.

"Tadashi!"

Hiro rubbed his ear against his shoulder looking disgusted and Tadashi laughed. Honey was trying her best to stay professional but she couldn't help the smile that lit her cheeks.

"Okay, Tadashi." Honey gestured to the chair and Tadashi took a seat.

He watched Hiro shake his limbs around in an attempt to wake up.

As soon as Hiro saw Tadashi seated, he grinned and began rubbing his hands together. The tables have turned.

Tadashi grinned back. "Do your worst."

"_Oh_, I plan to." Hiro replied.

"Just try to relax." Honey instructed with a pat on the boy's shoulder.

Tadashi closed his eyes but Hiro could tell he wasn't completely relaxed because there was still a smile on his face.

Honey walked around and started whispering instructions to Hiro. She had to bend down pretty far so that she could be closer to Hiro's height.

"And just try to speak very softly. It's works best if you drag out certain sounds." She stated.

Hiro nodded and walked over to Tadashi's right side. He could see his brother biting back a smile.

Hiro cleared his throat before leaning in close to Tadashi's ear.

"Come here often, _big boy_?" Hiro whispered, mimicking a high pitched, sexy voice.

"Pfftttt." Tadashi burst into laughter and Hiro soon followed.

It was so unexpected that Tadashi was bent forwards with his hands on his stomach. He couldn't control his laughter and their loud voices filled the room.

"Come on guys!" Honey stated. She tried to hide her own giggling behind her palm.

It took a few minutes for both brothers to stop laughing but when they finally quieted down, Tadashi took deep breaths and closed his eyes again. This time he was genuinely trying to stay motionless for Honey's study.

Hiro paused and simply looked at him. It was almost strange to see his brother without a smile.

Tadashi had always been there to help him relax when he couldn't sleep but Hiro had never returned the favor before.

Honey handed him her list of trigger words and Hiro searched for one that didn't sound too silly. He leaned in towards Tadashi's ear and whispered.

"Complicate." He said the word quietly and drug out each syllable. He could see a small bump appear on the monitor line and he frowned.

He repeated the word at different lengths away from Tadashi's ears but the monitor barely reacted. He even began repeating the words Tadashi had used on him but they didn't seem to have the same effect on his older brother.

"Hmm…" Hiro hummed in thought and was surprised to see the line rise higher.

Hiro smiled and continued making humming sounds around Tadashi's ears. He wondered if his brother was feeling the same tingling sensation that he had felt.

Hiro tried blowing directly into one of Tadashi's ears and it made the monitor spike even higher, but not quite to the top. He wanted to give his brother the same relaxed feeling he had gotten when his hair was being touched.

Oh! _Of course_.

Hiro slipped Tadashi's hat off and started touching his brother's hair.

Honey noticed Tadashi smiling again, but this smile was warm and brotherly as Hiro continued running his fingers along the older boy's scalp.

Hiro was disappointed to see little change in the monitor as he touched Tadashi's hair but when he accidentally brushed one of his ears, the line spiked all the way to the top of the screen.

Hiro paused and then grinned.

Immediately, he started gently running blunt nails along the shell of Tadashi's ear.

The monitor went wild and danced around the top of the screen.

"Now I've found _your_ weakness." Hiro whispered.

Tadashi's shoulders lowered and he seemed to melt into the chair. His head quirked to the side a bit and he actually leaned into the feeling as Hiro continued touching his right ear.

Hiro used the back of his hand to muffle his giggles and then stepped behind the chair and started touching both ears.

Tadashi let out a long breath and relaxed even further.

"Thanks guys, I think I have enough data for now." Honey stated after a few minutes. She realized that she had been so busy watching the two brothers interact that she forgot to continue taking notes.

Hiro grinned and stuck a finger in his mouth, ready for revenge but Tadashi's eyes flashed open and he grabbed Hiro by the waist and pulled him into his lap. He dug his knuckles into Hiro's head and tickled his sides. The boy laughed and tried to squirm away but his brother's grip was firm and the tickling continued.

Honey smiled as she watched them.

She always knew Tadashi was sweet at heart but seeing him with his brother made her realized just how kind and loving he could be.

Eventually Hiro went limp in surrender and Tadashi flipped him around and set him on his feet.

"Did this help at all with your research, Honey?" Tadashi asked.

She nodded. "Yes! This was perfect for the sound portion of the study. Although I still have to do a few more tests with visual triggers…"

Hiro's hand immediately shot into the air.

"We'll be your lab rats!"

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><p><strong>(I wrote this kinda quick, sorry for any grammar errors)<strong>

**Let me know what you guys thought!**

**Also, I've been totally obsessed with the Hamada brothers so if you haven any ideas for more fanfics involving Hiro and Tadashi I'd love to hear them ;)**


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